Improved bleachoto-frocess



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BRUNO SCHMIDT, NEW YORK, N. Y. Letters Patent No. 85,860, dated.Tanuon-y 12, 1869.

DEPRO'VED BLEACHING-PROOESS.

The Schedule referred to in these Letters Patent and making put of thesome,

To all whom it may concern:

and improved Bleaching-Process; and I do hereby de-- clare the followingto be a full, clear, and exact description thereof, which will enablethose skilled in the art to make and use the same.

This invention consists in removing the perman ganates used in bleachingcotton, linen, wood, straw goods, wax, or other fabrics or articles,together with the coloring-matter adhering to the fibre or article to bebleached, by subjecting the same to the action of a heated bath ofsulphuric acid, in such a manner that the bleaching-action of thepermanganates is rendered perfect, and the use of sulphuric acid orother gaseous agents noxious to the health can be dispensed with.

In carrying out my process, I introduce the articles to be bleached intothe solutionpf the permanganates, in the usual manner, leaving themtherein until all the permanganates contained in the solution areabsorbed. r the articles to be bleached are removed from the bathcontaining or having contained the pennanganates, they are usuallyexposed to the action of gaseous sulphurous acid, and the fumes arisingin completing the process are noxious to the health of .the .operators;and furthermore, the effect of the sulphurous acid is not quite asperfect as may be desired, and said acid, when once used, is spent,because it escapes in the form of a gas. v

All these difiiculties are obviated by my invention,

After removing the articles to be bleached fiom the bath ofthepermanganates, I introduce them into a bath of diluted sulphuric acid,whichI heat to about 210, and I have found that, by heating, the efi'ectof the bath is increased to such an extent that said bath j acts onehundred and fifty times quicker than it does if applied cold.

I am aware that manifold experiments have been made with thesulphuric-acid bath, but always in a cold state, and in this statetheaction of the bath is so slow that it is practically useless.

By using the heated bath, a perfect efiect is produced, all noxiousgases are avoided, and, furthermore, the cost of the whole process ismaterially reduced, sihce the sulphuric-acid bath can be used as many asfive times before its power is spent, while the gaseous agents, suchassulphurons acid, can only be used once.

Having thus described my invention,

What I claim as new, and desire to secure by Letters Patent, isv Thewithin-described process of removing the perinanganates used in thebleaching-process, together with the coloring-matter adhering tothefibres or articles to be bleached, by subjecting the same to theaction of a heated bath of diluted sulphuric acid, in the manner hereinset forth.

' BRUNO SCHMIDT.

Witnesses:

' W..HAUFF,

Emmsr F. KASTENHUBER.

